1. Field of the Invention
The present invention relates to novel polyanhydroaspartic acid polymers or copolymers and hydrolysates thereof which are at least 90%.+-.5% biodegradable, to a process for the preparation of such novel polyanhydroaspartic acids and their hydrolysates, as well as to the use of same as "builders" or "cobuilders" in detergent compositions.
2. Description of the Prior Art
Polyanhydroaspartic acid, also known to this art as polydehydroaspartic acid or simply polysuccinimide, is most typically prepared by thermal condensation of aspartic acid at a temperature on the order of 220.degree. to 230.degree. C. for several hours. It has been observed that the hydrolysates (polyaspartates), obtained by adding a basic reagent to the polyanhydroaspartic acid thus prepared, have a biodegradability in a natural medium which generally does not exceed 75% (EP-A-511,037).